I'm new with Sticky Password and before used Roboform then LastPass. In the latter, there is a feature I quite like which is to automatically log on onto a website one has requested Firefox to remember the login details. Is this possible with Sticky Password?

I hope I will describe my issue better here: on some website, I have indicated to roboform or lastpass that an account is the default (lastpass uses for instance the password stored in Firefox password management to determine this status, or in the program's itself) and they will log me in automatically whenever I open the connection page (both with automatic passcard filling and log in) without any other click or selection from my part.

So you mean selecting one of the logins as default...Then simply open the account details, go to the Options tab, check the Automatic Log-in checkbox and select the default login from the dropdown list.